EP1360041B1 - Drill or chisel hammer - Google Patents

Abstract

The invention relates to a hand tool machine comprising a percussor (14) and a coupling device (12, 100) that can be coupled and uncoupled to bring about and interrupt the drive connection (16, 102) of the percussor (14). According to the invention, the coupling device (12, 100) has a synchronizing device (18, 112) with a locking mechanism (20, 110) that transmits a driving torque, said mechanism having at least two corresponding locking elements (22, 24, 108) during synchronization, wherein at least one of the locking elements (22) can be moved from a locking position by the elastic force of a spring element (26, 116) during an overlatching moment.

Description

State of the art

The invention relates to a drill and / or chisel hammer according to the preamble of claim 1.

Such a hammer drill is eg off EP-0 331619-A known.

There are known drill and / or chisel hammers with pneumatic impactors, which can be activated or deactivated via a mechanical friction clutch. When the drill and / or chisel hammer is pressed against a processing surface with a tool, a tool holder holding the tool is guided in the direction of an operator into a housing of the drill and / or chisel hammer. This conical friction surfaces of the friction clutch come into contact and the pneumatic impact mechanism is driven by a frictional connection. During operation, the percussion mechanism generates a compressed air cushion which accelerates a racket in the axial direction onto a firing pin with a piston which is guided in a cylinder and which can be moved in the axial direction. The racket strikes the firing pin thereby experiencing a pulse. The impulse is forwarded to the tool located in the tool holder.

If the drill and / or percussion hammer is lifted off the processing surface with the tool, the friction surfaces of the friction clutch are separated by a so-called idle spring, and the drive connection of the striking mechanism is interrupted.

Advantages of the invention

The invention relates to a hand tool with a striking mechanism and a coupling device, which is switched on and disengaged for the production and interruption of a drive connection of the percussion.

It is proposed that the coupling device has a synchronizing device with a drive torque transmitting latching mechanism having at least two corresponding latching elements in a synchronizing, wherein at least one of the latching elements is movable at a latching moment against a spring force of a spring element from its rest position. With the latching mechanism can be created by a disengageable positive locking an advantageous synchronizing, which can transmit a relatively large torque even at a low coupling force. Due to the low coupling force required a particularly convenient hand tool machine can be achieved, which is already feasible with a small operating force in their working position.

It can be advantageously achieved by the disengageable positive engagement over a short distance synchronization, which is largely independent of a viscosity of a lubricant used in the coupling device. Further, with the synchronizer, a muted engagement can be achieved, and a clutch device with a low wear can be achieved.

Advantageously, the movable against a spring force detent element of a rolling element and formed with the locking element formed as a rolling element locking element by a recess. The rolling element can be formed, for example, by a ball, a roller, a barrel, etc. The locking elements can roll over when latched, and the wear can be reduced. The recess can be particularly adapted to the rolling of the rolling element, and it is a uniform and low-wear synchronization achievable. When using rolling elements designed as rollers, large transmission surfaces can be achieved, and larger torques can be transmitted in comparison with balls, whereas balls advantageously achieve a rolling movement in more than two directions and tilting can be avoided. In principle, however, it is also possible to use other detent elements that appear appropriate to the person skilled in the art, such as, for example, Sliding blocks etc.

With regard to a first embodiment of the invention, it is proposed that the locking element constructed as a rolling element can be moved out of its rest position against an annular spring. It is a simple and space-saving design with only one spring element achievable. The ring spring can be various be executed, for example, as a single spring with an anti-rotation, as a single spring without rotation and with a correspondingly shaped slot, which prevents despite tensioned spring escape of trained as rolling elements locking elements, or as a spring assembly, which advantageously a large spring force can be achieved with a small spring tension ,

If the latching element is moved at the beginning of the synchronization process along a conical surface against the annular spring, with a small axial force, a large radial force and thus a large synchronizing force can be achieved. In this case, the conical surface and / or the latching element can be designed to be axially movably mounted with the annular spring. With the conical surface, a translation of the axial force can be achieved by converting a larger axial movement with a smaller axial force into a smaller radial movement with a larger radial force. Furthermore, the latching element designed as a rolling element can be guided with a continuous movement into the latching element designed as a recess, and a uniform acceleration and an advantageous coupling can be achieved. Preferably, the locking element designed as a recess has a dome-shaped cross-sectional area.

Advantageously, the conical surface is integrally formed on one end of a component rotatable on a drivable shaft and axially displaceable, and a latching element designed as a recess extends into the conical surface. The synchronizing can be space-saving, structurally simple and realized with a few additional components.

In a further embodiment of the invention, it is proposed that at the beginning of the synchronization process, the locking element along the cone surface is guided radially outward. An existing space in the radial outward direction can be used advantageously and it can be used a large, low-tolerance spring. In principle, however, it is also conceivable to arrange the locking elements radially outside of an annular spring and to carry out radially inwardly against the annular spring movable.

If a component transmitting an impulse of the impact mechanism is connected to the displaceable component via a connection which transmits at least one force in the impulse direction, the impulse can be used to reach the neutral position and a return spring or an idling spring can be supported in their effect. Advantageously, the return spring can be made smaller than in a conventional engagement clutch, and it can be a small operating force and high comfort can be achieved.

It is also proposed that a foot inner circle of at least two locking elements formed as recesses has the same diameter as a foot inner circle of the rolling elements designed as detent elements in an idle position. At a standstill, the rolling elements unhindered, without burdening the spring, led into the recesses and it can be a simple engagement and disengagement can be achieved. Furthermore, it can be achieved in particular that during a working position, the annular spring is unloaded.

With regard to a second embodiment of the invention, it is proposed that the locking element is formed by a ball which is supported on a on a drivable shaft axially displaceable against a spring cone ring. The spring can take over the function of a synchronizing spring and an idle spring and additional components, space, weight and cost can be saved. With the cone ring a translation can be achieved, with a small axial force in a large radial force and a large synchronizing force can be translated.

If the conical ring is fixed in the axial direction by a stop when the drive connection is produced, the latching element can be used to produce a positive connection and additional interlocking elements can be saved.

It is also proposed that the locking element formed as a ball is supported radially inwardly on the displaceable cone ring and radially outwardly engageable with the recess formed as a corresponding locking element in operative connection. An existing space in the radial direction to the outside can be used advantageously. In principle, however, it is also conceivable that the locking elements are supported radially outwardly on an axially displaceable cone ring.

If the latching element is mounted in a part of a drive element, in particular a drive bearing of the impact mechanism, existing components can be used and additional components, construction space and costs can be saved.

Are formed on the coupling device interlocking elements that come after the synchronization next to the locking mechanism into engagement, the locking mechanism can be relieved during operation and the wear of the locking elements can be reduced.

drawing

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawings, the descriptions and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Fig. 1

einen Teilschnitt durch einen Bohr- und Meißelhammer,

Fig. 2

eine Kupplungsvorrichtung des Bohr- und Meißelhammers aus Fig. 1 in einer Leerlaufstellung,

Fig. 3

die Kupplungsvorrichtung aus Fig. 2 während einer Synchronisierung,

Fig. 4

die Kupplungsvorrichtung aus Fig. 2 in einer Schlagbohrstellung,

Fig. 5

ein Kupplungselement der Kupplungsvorrichtung aus Fig. 2 schräg von oben,

Fig. 6

einen Teilschnitt durch einen Bohr- und Meißelhammer mit einer alternativen Kupplungsvorrichtung,

Fig. 7

die Kupplungsvorrichtung aus Fig. 6 in einer Leerlaufstellung,

Fig. 8

die Kupplungsvorrichtung aus Fig. 6 während einer Synchronisierung,

Fig. 9

die Kupplungsvorrichtung aus Fig. 6 in einer Schlagbohrstellung,

Fig. 10

ein Kupplungselement der Kupplungsvorrichtung aus Fig. 6 in axialer Richtung und

Fig. 11

eine zu Fig. 6 alternative Kupplungsvorrichtung mit zusätzlichen Formschlußelementen.

Show it:

Fig. 1

a partial section through a drill and chisel hammer,

Fig. 2

a coupling device of the drill and chisel hammer Fig. 1 in an idle position,

Fig. 3

the coupling device Fig. 2 during a sync,

Fig. 4

the coupling device Fig. 2 in a percussion drilling position,

Fig. 5

a coupling element of the coupling device Fig. 2 diagonally from above,

Fig. 6

a partial section through a drill and chisel hammer with an alternative coupling device,

Fig. 7

the coupling device Fig. 6 in an idle position,

Fig. 8

the coupling device Fig. 6 during a sync,

Fig. 9

the coupling device Fig. 6 in a percussion drilling position,

Fig. 10

a coupling element of the coupling device Fig. 6 in the axial direction and

Fig. 11

one too Fig. 6 alternative coupling device with additional positive locking elements.

Description of the embodiments

Fig. 1 shows a partial section through a drill and chisel hammer with a housing 10 arranged in an unspecified electric motor having a drive shaft 52. To the drive shaft 52, a pinion is formed, which meshes with a arranged on a shaft 52 to the drive shaft 52 parallel fixed wheel 118. The shaft 30 has on a tool holder 54 side facing a molded gear 56, via which the shaft 30 meshes with a arranged on a hammer tube 60 gear 58. The gear 58 is rotatably mounted on the hammer tube 60 and is connected via rolling elements of a Überrastkupplung 62 with a non-rotatably mounted on the hammer tube 60 locking disc 64. The hammer tube 60 is in turn rotatably connected to the tool holder 54.

On the shaft 30 a striking mechanism 14 is rotatably mounted with a drive bearing 74. Further, a coupling device 12 is mounted on the shaft 30, which is switched on and disengaged for the manufacture and interruption of a drive connection 16 of the impact mechanism 14. The coupling device 12 has on the side facing away from the tool holder 54 side of the gear 56 on the shaft 30 axially displaceable and rotatably mounted erste.Kupplungselement 32. The first coupling element 32 has at its tool holder 54 end facing an internal toothing, with the first coupling element 32nd rotatably and axially displaceably guided on the gear 56. At an end remote from the tool holder 54, a part of a synchronizing device 18 is formed on an outer circumference of the first coupling element 32, specifically a cone surface 28 whose diameter increases in the direction of the tool holder 54 (FIG. Fig. 1 to 5 ). Instead of a conical surface, it is also possible for other surfaces which appear appropriate to the person skilled in the art to be formed, for example convex and / or concave surfaces, whose diameters preferably increase in the direction of the tool holder. Due to the design of the surface can advantageously be influenced the synchronization.

In the conical surface 28, starting in the direction of the tool holder 54 extending, designed as recesses locking elements 24 of a latching mechanism 20 of the synchronizing device 18 (FIG. Fig. 1 and 5 ). The recesses formed as recesses 24 have a dome-shaped cross-sectional area. In order to achieve a smooth engagement, the transitions in the circumferential direction in the recesses in the region of the conical surface 28 are rounded ( Fig. 5 ).

The first coupling element 32 projects with its end facing away from the tool holder 54 in a second, corresponding coupling element 44, which also forms part of the drive bearing 74 of the impact mechanism 14. In the second coupling element 44 formed as balls locking elements 22 of the locking mechanism 20 are mounted in a plurality of circumferentially distributed, radially extending bores. In an idle position of the drill and chisel hammer formed as balls locking elements 22 protrude with a part radially inwardly over an inner circumference of the second coupling element 44 and are each supported on a formed in the bores collar radially inwardly. Trained as balls locking elements 22 form a Fußinnenkreis 36, which has the same diameter as a Fußinnenkreis 34 formed as recesses locking elements 24 (FIG. Fig. 1 to 4 ). Furthermore, the number of balls coincides with the number of recesses, so that the first and the second coupling element 32, 44 can be joined force-free at standstill of the drill and chisel.

The locking elements 22 designed as balls are surrounded radially outwards by an annular spring 26. In particular, the design of the formed as recesses locking elements 24 and the annular spring 26, the synchronization behavior can be adjusted. In the Fig. 2 to 4 is shown a coupling operation of the coupling device 12. If the drill and chisel hammer with a non-illustrated tool pressed against a processing surface, a reaction force is transmitted from the tool holder 54 via a locking ring 38, via the hammer tube 60, via a locking ring 40 on the locking disc 64 and the locking disc 64 via a positive connection 76 on the first coupling element 32, and in particular the components 32, 54, 60, 64 further inserted into the housing 10. To an outer periphery of the locking disc 64, an annular groove 70 is formed, in which a formed on the first coupling element 32 collar 72 engages. The annular groove 70 and the collar 72 form the positive connection 76 in the axial direction between the locking disc 64 and the first coupling element 32 (FIGS. Fig. 1 ).

About the locking plate 64 and the connection 76, the first coupling element 32 is inserted into the second coupling element 44 against an idle spring 68. Trained as a helical compression spring idle spring 68 is disposed on the shaft 30 and is supported with its tool holder 54 facing away from the end of a support ring 78 and a ring groove 30 secured in the locking ring 42 on the shaft 30 from. With its tool holder 54 facing the end of the idle spring 68 protrudes axially into an annular recess between the first coupling element 32 and the shaft 30 and acts on an integrally formed on the first coupling element 32 stop with a pressing force in the direction of the tool holder 54th

The formed as balls locking elements 22 are moved at the beginning of the synchronization along the cone surface 28 radially outward against the annular spring 26 ( FIGS. 2 and 3 ). The formed as balls locking elements 22 come with it formed as recesses locking elements 24 in operative connection. It is achieved a disengageable positive engagement by the locking elements formed as balls 22 during the synchronization of their detent positions, namely from the recesses formed as recesses 24, against the annular spring 26 at a Überrastmoment can disengage radially outward ( Fig. 3 ). The first coupling element 32 accelerates over the disengageable positive locking the second coupling element 44, wherein after the conical surface 28, a maximum torque of the locking mechanism 20 is achieved.

After a synchronization of the first and the second coupling element 32,44 come to the first coupling member 32 integrally formed axially extending towards the second coupling member 44, claw-like interlocking elements 48 with appropriately designed, integrally formed on the second coupling element 44, axially toward the first Coupling member 32 extending claw-like interlocking elements 50 in engagement. The latching mechanism 20 is bridged, and the impact mechanism 14 is driven via the interlocking elements 48, 50 ( Fig. 4 ). Exceeds the drive torque during operation, a permissible value, the gear 58 is deflected against a Überrastfeder 66 in the axial direction of the tool holder 54 and interrupted the drive connection of the tool to the electric motor. Fig. 1 and 4 show the drill and chisel hammer or the coupling device 12 in a Schlagbohrstellung.

When the drill and chisel hammer is lifted off the processing surface, the idler spring 68 causes the first coupling element 32 to engage the locking disk 64 via the connection 76. about the locking ring 40, the hammer tube 60 and the locking ring 38, the tool holder 54 is moved axially into its starting position in the direction of the processing surface. The idle spring 68 is supported in its mode of action by an idle stroke of a guided in the hammer tube 60 racket 80, by a pulse of the racket 80 via an anvil 46, the tool holder 54, the hammer tube 60, the locking disc 64 and the connection 76th is transmitted to the first coupling element 32.

In the Fig. 6 to 10 another embodiment with an alternative coupling device 100 is shown. Substantially identical components are basically numbered with the same reference numerals. Furthermore, with regard to features and functions that are the same, the description of the exemplary embodiment in FIGS Fig. 1 to 5 to get expelled.

On a shaft 30 a striking mechanism 14 is rotatably mounted with a drive bearing 74. Further, a coupling device 100 is mounted on the shaft 30, which is on and disengageable for producing and interrupting a drive connection 102 of the striking mechanism 14. The coupling device 100 has on the side facing away from a tool holder 54 of a gear 56 on the shaft 30 axially displaceable and rotatably mounted first coupling element 104. The first coupling element 104 has at its tool holder 54 end facing an internal toothing, with the first coupling member 104 rotatably and axially displaceable on the gear 56 is guided ( Fig. 6 ).

On the first coupling element 104, a sleeve 106 is formed on its side facing away from the tool holder 54 side, which engages over a second, corresponding coupling element 122. The second coupling element 122 forms part of the drive bearing 74 of the hammer mechanism 14.

The sleeve 106 has on its inner circumference formed as recesses locking elements 108 of a latching mechanism 110 of a synchronizer 112. The latching elements 108 run to an end remote from the tool holder 54 obliquely radially outward or have a decreasing depth, and in a last region before the tool holder 54 facing away from the sleeve 106 has a Fußkreis 126 of the locking elements 108 corresponding inner diameter ( Fig. 10 ). The locking elements 108 have a dome-shaped cross-sectional area.

Radially inside the sleeve 106 is rotatably mounted on the shaft 30 and displaceable in the axial direction cone ring 114. The cone ring 114 is displaceable against a spring 116 on a side facing the tool holder 54. In the opposite direction from the tool holder 54, the cone ring 114 is supported on the shaft 30 via a retaining ring 120 secured in an annular groove of the shaft 30. The spring 116 is formed by a helical compression spring which has a diameter increasing in the direction of the tool holder 54 and is arranged between the first coupling element 104 and the conical ring 114. The spring 116 is supported with its end facing the tool holder 54 in an annular recess on a collar of the first coupling element 104 from. At her the tool holder 54 facing away from the spring 166 is supported on the cone ring 114 ( Fig. 6 to 10 ). About the choice of the spring 116, a cone angle of the cone ring 114, and on the recesses formed as recesses 108, in particular via a transition into the recesses, the Synchonisationsverhalten can be adjusted.

In the second coupling element 122 formed as balls locking elements 22 of the latching mechanism 110 are mounted in a plurality of circumferentially distributed, radially extending bores. The latching elements 22 formed as balls project with a part radially inward over an inner circumference of the second coupling element 122 and are supported inwardly on the cone ring 114 displaceable against the spring 116 (FIG. Fig. 6 to 9 ).

In the Fig. 7 the coupling device 100 is shown in the disengaged state. If the drill and chisel hammer pressed against a processing surface with a tool, not shown, a reaction force from the tool holder 54 via a locking ring 38, the hammer tube 60 and a locking ring 40 on the locking disc 64 and the locking plate 64 via a positive Transfer compound 76 to the first coupling element 104, and in particular the components 54, 60, 64 and 104 are further inserted into the housing 10. To an outer periphery of the locking disc 64, an annular groove 70 is formed, into which a formed on the first coupling element 104 collar 72 engages. The annular groove 70 and the collar 72 form the positive connection 76 in the axial direction between the locking disk 64 and the first coupling element 104.

The first coupling element 104 is pushed against the spring 116 via the second coupling element 122. The spring 116 is prestressed and transmits the axial movement of the first coupling element 104 to the cone ring 114 with a compressive force. The locking elements 22 designed as balls are urged radially outwardly against the sleeve 106 of the first coupling element 104 by the cone ring 114. Fig. 8 ).

As a result of the axial movement of the first coupling element 104 in the direction of percussion mechanism 14, the latching elements 22 designed as balls come into operative connection with the latching elements 108 of the first coupling element 104 designed as recesses. It is achieved a disengaged positive engagement by the locking elements formed as balls 22 during the synchronization of their detent positions, namely from the recesses formed as locking elements 108 against the cone ring 114 can disengage radially inwardly at a Überrastmoment, and the cone ring 114 against the spring 116 can be moved in the direction of the tool holder 54. The first coupling element 104 accelerates the second coupling element 122 via the disengageable positive locking (FIG. Fig. 8 ).

When the drive connection 102 is produced, the cone ring 114 is fixed axially in the direction of the tool holder 54 by a stop 124 of the first coupling element 104 ( Fig. 6 and 9 ). The latching elements 22 designed as balls are supported radially inwardly on the axially fixed conical ring 114 and are securely chambered in the corresponding latching elements 108 designed as recesses. By stop 124 a disengagement of the locking elements 22 is avoided and the locking elements 22, 108 form a positive connection between the first and the second coupling element 104, 122. If the drive torque exceeds a permissible value during operation, the gear 58 is deflected against an override spring 66 in the axial direction to the tool holder 54 and the drive connection is interrupted ,

Fig. 6 and 9 show the drill and chisel hammer or the coupling device 12 in a Schlagbohrstellung. If the drill and chisel hammer lifted from the processing surface of the spring 116, the first coupling element 104, via the connection 76, the detent disk 64, via the locking ring 40, the hammer tube 60 and the locking ring 38, the tool holder 54 in its initial position axially in the direction moved to the editing interface. The spring 116 is supported in its mode of action by an idle stroke of a guided in the hammer tube 60 racket 80, by a pulse of the racket 80 via an anvil 46, on the tool holder 54, the hammer tube 60, the locking disc 64 and the connection 76th is transmitted to the first coupling element 104.

Fig. 11 shows a variant of the coupling device 100 from Fig. 7 , After a synchronization of the first and the second coupling element 104, 122 are formed on the first coupling element 104, axially in the direction of the second coupling element 122 extending, claw-like positive locking elements 128 with appropriately designed, integrally formed on the second coupling element 122, axially toward the first Coupling member 104 extending claw-like interlocking elements 130 into engagement. The latching mechanism 110 is bridged, and the striking mechanism 14 is driven via the interlocking elements 128, 130.

reference numeral

10

casing

12

coupling device

14

striking mechanism

16

drive connection

18

synchronizing

20

detent mechanism

22

locking element

24

locking element

26

Ringfeder

28

conical surface

30

wave

32

coupling member

34

root inner circle

36

root inner circle

38

circlip

40

circlip

42

circlip

44

coupling member

46

Döpper

48

Positive-locking element

50

Positive-locking element

52

drive shaft

54

tool holder

56

gear

58

gear

60

hammer tube

62

Detent coupling

64

locking disc

66

About detent spring

68

Idling spring

70

ring groove

72

Federation

74

drive bearing

76

connection

78

support ring

80

bat

100

coupling device

102

drive connection

104

coupling member

106

shell

108

locking element

110

detent mechanism

112

synchronizing

114

cone ring

116

feather

118

fixed gear

120

circlip

122

coupling member

124

attack

126

root circle

128

Positive-locking element

130

Positive-locking element

Claims (13)

1. Portable power tool having a percussion mechanism (14) and a clutch device (12, 100) which can be engaged and disengaged for producing and interrupting a drive connection (16, 102) of the percussion mechanism (14), characterized in that the clutch device (12, 100) has a synchronizing device (18, 112) having a latching mechanism (20, 110) which transmits a drive torque and has at least two corresponding latching elements (22, 24, 108) during a synchronizing operation, wherein at least one of the latching elements (22) can be moved out of its latching position against a spring force of a spring element (26, 116) during an overload torque.
2. Portable power tool according to Claim 1, characterized in that the latching element (22) movable against a spring force is formed by a rolling body and the latching element (24, 108) corresponding with the latching element (22) designed as a rolling body is formed by a recess.
3. Portable power tool according to Claim 1 or 2, characterized in that the latching element (22) can be moved out of its latching position against an annular spring (26).
4. Portable power tool according to Claim 3, characterized in that the latching element (22) is displaced along a conical surface (28) against the annular spring (26) at the start of the synchronizing operation.
5. Portable power tool according to Claim 4, characterized in that the conical surface (28) is integrally formed on an end of a component (32) which is rotationally fixed and axially displaceable on a drivable shaft (30), and a latching element (24) designed as a recess extends into the conical surface (28).
6. Portable power tool according to Claim 5, characterized in that the latching element (22) is directed radially outwards along the conical surface (28) at the start of the synchronizing operation.
7. Portable power tool according to Claim 5 or 6, characterized in that a component (64) transmitting an impulse of the percussion mechanism (14) is connected to the displaceable component (32) via a connection (76) which transmits a force in the impulse direction.
8. Portable power tool according to one of the preceding claims, characterized in that a root inner circle (34) of at least two latching elements (22) designed as recesses has a diameter identical to a root inner circle (36) of the latching elements (22) designed as rolling bodies in an idling position.
9. Portable power tool according to Claim 2, characterized in that the latching element (22) designed as a rolling body is formed by a ball which is supported on a conical ring (114) displaceable axially against a spring (116) on a drivable shaft.
10. Portable power tool according to Claim 9, characterized in that the conical ring (114) is fixed axially by a stop (124) when the drive connection is produced.
11. Portable power tool according to Claim 9 or 10, characterized in that the latching element (22) designed as a ball is supported radially inwards on the displaceable conical ring (114) and can be brought radially outwards into operative connection with the corresponding latching element (108) designed as a recess.
12. Portable power tool according to one of the preceding claims, characterized in that the latching element (22) is mounted in a part of the drive element (74) of the percussion mechanism (14).
13. Portable power tool according to one of the preceding claims, characterized in that the clutch device (12) has positive-locking elements (48, 50, 128, 130) which come into engagement in addition to the latching mechanism (20, 110) after the synchronizing operation.

Images